/Engine/Source/Runtime/Engine/Public/MaterialShared.h
void FillUniformBuffer ( const [FMaterialRenderContext](API\Runtime\Engine\FMaterialRenderContext) & MaterialRenderContext, const [FUniformExpressionCache](API\Runtime\Engine\Materials\FUniformExpressionCache) & UniformExpressionCache, const [FRHIUniformBufferLayout](API\Runtime\RHI\FRHIUniformBufferLayout) * UniformBufferLayout, uint8 * TempBuffer, int TempBufferSize ) const